A power steering system of an automotive vehicle comprises a pump for supplying hydraulic fluid under pressure to a power steering gear assembly. U.S. patent application Ser. No. 10/443,320, filed May 22, 2003, describes a power steering pump that includes a cam plate that defines a cam chamber, and a vaned rotor within the cam chamber for pumping fluid. The cam plate is interposed between pressure plates within a canister housing. The cam plate and the pressure plates are retained by a cover that is secured by a retainer ring. In common practice, the retainer ring is a snap ring that fits in a groove in the inner surface of the can housing. Insertion of the retainer ring is accommodated by clearance between the several elements within the housing. This clearance increases stress on, and wear of, seals between the elements. Also, under the high pressures created during operation, even slight spacing increases noise and vibration.
Therefore, a need exists for a power steering pump wherein the cam plate and the pressure plates are secured within the can housing with reduced clearance, thereby improving sealing and reducing vibration and noise resulting from high pressure operation.